2003 Jaguar S-Type Climate control is either all hot or all

The heating and defrosting system:
controls the vehicle air temperature and, during A/C operation, reduces the relative humidity of the air inside the vehicle.
Delivers heated or cooled air to maintain the vehicle interior temperature and comfort level.
Controls the A/C blower motor speed.
Allows temperature to be adjusted individually by the driver and the passenger to maintain comfort.
Uses a reheat method to provide conditioned air to the passenger compartment. All airflow from the blower motor passes through the A/C evaporator core. Temperature is regulated by reheating a portion of the air and blending it with the remaining cool air to achieve the desired temperature.
Blends the air temperature by regulating the flow of engine coolant to separate halves of the heater core. A dual solenoid actuated valve is used to control the flow of coolant.
The blower motor draws outside air through the air inlet filter and duct during all system operations except for MAX A/C cooling (when recirculated air is used).